4" 8 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



and shorter primary- coverts usually are conuected witli rounded wiugs, 

 and vice versa. We may also find many instances which prove that 

 such a law for the construction of the wing does not exist. 



Considering the great importance of the number of the primaries of 

 the Oscines, aud the deep-seated affinities expressed by the characteristic 

 position of the middle wiug-coverts, it is difficult to escape the impres- 

 sion that the construction of the wing is of especial importance in 

 determining the relationships of the highest organized birds. As this 

 difference in the construction usually consists in different development 

 of one part in relation to, others, it generally becomes a character rather 

 easily expressed in words and represented by figures; thus being of 

 great advantage to those who try to fix the limits of the different groups 

 by means of structural characters. 



It will be unnecessary to point out the impossibility of expressing 

 all the manifold and intricate relationships of the genera by arranging 

 them in a straight line. It is, consequently, a matter ot course that the 

 succession of the genera in the following synopsis expresses only to a 

 certain degree their mutual relations. It may also be considered that 

 the omission of the PahTeogean forms makes the series incomplete. At 

 first it was my intention to give a diagram showing the affinities, but, in 

 view of the imperfectness of such an attempt, without including all old- 

 world genera in addition to the American ones, I have thought it better 

 to put it off" to a later time. 



On the other hand, the characters of the sections and genera given 

 below are intended to embrace all forms belonging to them, and not 

 only those occurring in America. If I have not always succeeded 

 herein it is partly due to the relatively scarce material, which repre- 

 sents only a fraction of the extra- American birds. 



As to the noinenclature and the manner of quotation, I only refer to 

 my remarks in my paper, in Proceedings of the U. S. Nat. Mus., vol. 5, 

 1882, p. 29. It will be seen that examples strengthening the views there 

 expressed are to be easily found in the present memoir. As a very 

 striking one, I refer to the foot-note given under Myadestes, showing 

 the character and the uselessness of phdological "emendations" in 

 ornithological nomenclature. 



Before concluding these remarks, I take the opportunity of thanking 

 mj' friend Kobert liidgway for his most valual)le assistance, without 

 which I should never have attempted the following essay. 



I have also to acknowledge my indebtedness to the authorities of the 

 Smithsonian Institution and United States National Museum for the 

 opportunity of examining the collections upon which this paper is 

 largely based. 



Washington, D. C, 3Iarch 20, 1882. 



